Label-free detection of microRNA based on the fluorescence quenching of silicon nanoparticles induced by catalyzed hairpin assembly coupled with hybridization chain reaction

MicroRNAs (miRNAs) play important roles in the regulation of cellular activities and are considered as potential biomarkers for various diseases. The detection of miRNA has become a highly important aspect for clinical diagnostics. In this work, a simple method for detection of miRNA is developed based on the fluorescence quenching of silicon nanoparticles (SiNPs) induced by the inner filter effects (IFE). The target miRNA triggers the hybridization chain reaction (HCR) of two DNA hairpin probes containing three-fourths and one-fourth split-G-quadruplex sequences, leading to the formation of horseradish peroxidase (HRP)-mimicking DNAzyme. The resulting DNAzyme can catalyze the H2O2-mediate oxidation of o-phenylenediamine (OPD) to 2,3-diaminophenazine (DAP). The absorption band of DAP fully overlaps with the emission band of SiNPs, resulting in the significantly fluorescence reduction of SiNPs. And the logarithm of the target miRNA concentration is proportional to the changes in fluorescence intensity of SiNPs. This newly developed label-free and enzyme-free sensing platform exhibits a high selectivity toward miRNA detection, which demonstrates a good performance to discriminate single-base difference. The present IFE-based SiNPs fluorescence sensing strategy gives a new insight on the development of the label-free optical probe for miRNA detection and has a great potential for early diagnosis in miRNA-related disease. (C) 2017 Elsevier B.V. All rights reserved.